Wheeled stretcher

ABSTRACT

A patient lifting and transporting vehicle having a U-shaped base frame with four wheels, two telescopic tubes extending upward from the base frame, a rectangular upper frame provided with a removable strong transfer sheet for supporting a patient, said upper frame being fixed on the upper ends of the telescoping tubes, and operating mechanism comprising a lifting arm assembly hinged at its lower end to the base frame and at its upper end to a follower block slidable in one tubular side of the upper frame, said tubular side containing a drive screw engaging the follower block and crank-operated bevel gears for rotating the drive screw. When the upper frame is in its lowest position the lifting arm assembly lies at an angle of about 45* from the horizontal; as the lifting arm is moved, by the drive screw and follower block, toward a vertical position the upper frame is raised correspondingly to a highest position when the arm is vertical. Springs under compression in the telescoping tubes counterbalance part of the weight of the loaded upper frame. The location of the telescoping tubes on one side of the base frame and spaced from its ends enables the upper frame to be moved over a bed or operating table or into the range of an X-ray machine.

United States Patent [191 Smith June 11, 1974 WHEELET) STRETCHER [75] Inventor: David J. Smith, Billerica, Mass.

[73] Assignee: C. R. Bard, lnc., Murray Hill, NJ. [22] Filed: Aug. 21, 1972 [21 App]. No.: 282,086

[52] US. Cl 5/81, 5/63, 5/86 [51] Int. Cl A6lg 7/10- [58] Field of Search 5/61, 63, 81, 86; 296/20 [56] References Cited UNITED STATES PATENTS 2,587,094 2/l952 Berg et al. 5/86 X 2,908,916 10/1959 Fischer et al. 5/86 3,259,922 7/1966 Fischer 5/86 Primary Examiner-Casmir A. Nunberg Attorney, Agent, or FirmChester E. Martine, Jr.

[57] ABSTRACT A patient lifting and transporting vehicle having a U- shaped base frame with four wheels, two telescopic tubes extending upward from the base frame, a rectangular upper frame provided with a removable strong transfer sheet for supporting a patient, said upper frame being fixed on the upper ends of the telescoping tubes, and operating mechanism comprising a lifting arm assembly hinged at its lower end to the base frame and at its upper end to a follower block slidable in one tubular side of the upper frame, said tubular side containing a drive screw engaging the follower block and crank-operated bevel gears for rotating the drive screw. When the upper frame is in its lowest position the lifting arm assembly lies at an angle of about 45 from the horizontal; as the lifting arm is moved, by the drive screw and follower block, toward a vertical position the upper frame is raised correspondingly to a highest position when the arm is vertical. Springs under compression in the telescoping tubes counterbalance part of the weight of the loaded upper frame. The location of the telescoping tubes on one side of the base frame and spaced from its ends enables the upper frame to be moved over a bed or operating table'or into the range of an X-ray machine.

2 Claims, 5 Drawing Figures PATENTEDJUN 1 1 m4 SHEET 10F 2 FIG.

WHEELED STRETCHER The field of invalid lifting and transporting devices including stretchers, chair-type lifts and sling or hammock carriers, has been extensively developed. For present purposes it is sufficient to note that overhang or cantilevered stretchers, with wheels, are particularly useful in their ability to place'the patient in a desired position over a bed or operating table or X-ray apparatus while the patient is fully supported, with the possibility of depositing the patient on the bed or table merely by lowering the stretcher. Patents showing stretchers of this general type include Sechrist et al.

US. Pat. No. 2,035,840; Richard US. Pat. No.

2,127,309; Sutton US. Pat. No. 2,234,483; I-Iassold US. Pat. No. 2,498,853; Waterman US. Pat. No. 2,613,372; Fischer et al. US. Pat. No. 2,908,916; Fischer US. Pat. No. 3,259,922; Welborn US. Pat. No. 3,401,410; and Danielson US. Pat. No. 3,451,070;

The present invention relates to a wheeled stretcher of the cantilever type wherein the upper frame and transfer sheet are raised and lowered by means of a lifting arm assembly hinged at its lower end to the base frame and at its upper end to a follower block movable horizontally in oneside of the upper frame under the control of a crank-operated screw.

A practical embodiment of the invention is shown in the accompanying drawings, wherein FIG. 1 represents a perspective view of the stretcher in lowered position;

FIG. 2 represents a detail side elevation of the stretcher in lowered position, parts being broken away;

FIG. 3 represents a detail side elevation of the stretcher in fully raised position;

FIG. 4 represents a detail elevation of the follower block and adjacent elements, parts being broken away, and

FIG. 5 represents a detail vertical section of the bevel gear drive, brake and adjacent elements, parts being broken away.

Referring to the drawings, the stretcher comprises a wide U-shaped base frame supported by four casters 11 and having tubular posts 12 projecting vertically upward from the frame side bar 13 to which they are welded at points 14, 14 located approximately midway between the rounded corners of the base frame and the middle of the side bar.

- The upper frame 15 is rectangular and one of its tubular side bars 16 is provided with tubular posts 17 (slightly larger than the posts 12) projecting vertically downward in positions to fit telescopically over the posts 12.

Within the posts 12 and 17 are strong coil springs 18 under compressionand calculated to counter-balance some or all of the empty weight of the upper frame assembly, including posts 17 and the operating mechanism, to be described. Between one of the posts 17 and the adjacent corner of the frame the side bar 16 is interrupted by the insertion of a crank housing 19.

Vertical adjustment of the upper frame is effected by means of the lifting arm 20, the lower end of which is connected by support bars 21 to the support tube 22 which projects downward from the side bar 13 at a point near, but offset outwardly from one of the posts 12. The support bars 21 are firmly welded on the sides of the arm and form an elongated yoke on each side of the bar 13 and being pivoted at 23 to tube 22. At its upper end the lifting arm 20 is provided with a yoke 24, pivoted at 25 to a lug 26 projecting downward from the follower block 27.

The upper frame side bar 16 is provided with a longiudinal slot 28 along its bottom between points adjacent the respective posts 17, and the follower block 27, movable longitudinally in the bore of the bar 16, has a guide piece 29 extending through the slot and carrying the lug 26. The follower block is driven by a screw 30 (e.g., a Saginaw screw) engaging a ball nut 31 mounted on the follower block (FIG. 4) and rotated in either direction by the bevel gear drive shown in detail in FIG. 5.

The crank shaft 32, having the upwardly projecting handle 33, is joumaled in upper and lower ball bearings 34 fixed in the crank housing 19. A first bevel gear 35 is pinned to the shaft 32 with its teeth engaging the teeth of a second bevel gear 36 which is pinned on the reduced end portion 37 of the screw 30. The adjacent unthreaded end portion 38 of the screw is supported in the ball bearing 39 which'is mounted in a fixed collar 40. A friction brake to control rotation of the screw is constituted by a friction brake disc 41 pinned on the portion 38 and spaced from the collar 40 by the thrust bearing 42; the brake collar 43 is fixed to the bar 16, as by the set screw 44, and has a cylindrical hub portion 45 with the samediameter as the brake bearing 46; a torsion spring 47 is wrapped around the hub portion 45 and bearing 46 and the latter is spaced frome the brake disc 41 by a thrust washer 48. A compression spring 49 bears against the collar 43 and against a back-up washer 50 on the screw shaft 30, tending to draw the parts, 41, 43, 46 and 48 together. The orientation of the torsion spring 47 is such that, when the unit is being cranked up, the brake bearing 46 turns with the screw shaft because the spring 47 is unwinding in that direction. When the unit is being cranked downward the spring tightens up and stops the brake bearing 46 from turning with the screw shaft; the friction thus created at the thrust washer 48 keeps the shaft from spinning freely so that cranking is required for movement in either direction,-regardless of the load.

The stretcher is completed by the provision of a strong transfer sheet, 51, of canvas or the like, secured to the upper frame 15 by means of suitably disposed straps 52 and buckles 53.

In operation, the turning of the crank shaft 32 by means of handle 34 rotates the screw 30, sliding the block 27 in the tubular side bar 16 and causing the lifting arm 20 to move around its lower pivot 23 to different angular positions between the lowest, shown in FIGS. 1 and 2, and the highest, shown in FIG. 4. The lifting arm is given an increased range by means of the support bars 21 which enables the arm to have an effective length substantially greater than it would if the lower pivot point were located above the bar 13. The outward offsetting of the support tube 22 requires the bars 21 to be fixed to the lifting arm 20 at a slight angle, so that the arm can approach and lie parallel to the adjacent posts 12, 17, in the upper position (FIG. 3).

The springs 18 exert their greatest lifting force when the stretcher is in its lowest position, and when the moment of lifting force from movement of the follower block is the least. Conversely, at the higher positions, the springs are less effective while the lifting arm, as it approaches the vertical position, has increasing lifting power from a given input of force at the crank. As a result of this spring and lever coordination the load on the stretcher can be moved up and down in any part of its vertical range with approximately if not mathematically uniform application of energy.

It would evidently be possible to construct a stretcher embodying the same operating elements with only a single telescoping post, but it is considered to be more practical to use two posts.

It will be understood that various changes may be made in the form, construction and arrangement of the several parts without departing from the spirit and scope of the invention and hence I do not intend to be limited to the details shown or described herein except as the same are included in the claims or may be required by disclosures of the prior art.

What I claim is:

1. -A patient lifting and transporting vehicle comprising, a base frame, an upper frame having a side rail and provided with patient supporting means, at least one upright assembly having a part mounted on the base frame and a part mounted on the upper frame, said parts cooperating to permit and control movement of the upper frame relative to the base frame, frame moving means comprising a lifting arm pivotally connected at one end to the base frame and pivotally connected at the other end to the upper frame, means on the upper frame for moving the point of connection between the arm and said upper frame to change the angle of said arm toward and away from the vertical, whereby the height of the upper frame above the lower frame can be varied, a follower block slidable along a side rail of the upper frame, said other end of the lifting arm being pivotally connected to said block, the means for moving the point of connection being a screw operatively associated with the follower block and a crank for rotating said screw.

2. A vehicle according to claim 1 which includes a friction brake arranged to restrict rotation of the screw. 

1. A patient lifting and transporting vehicle comprising, a base frame, an upper frame having a side rail and provided with patient supporting means, at least one upright assembly having a part mounted on the base frame and a part mounted on the upper frame, said parts cooperating to permit and control movement of the upper frame relative to the base frame, frame moving means comprising a lifting arm pivotally connected at one end to the base frame and pivotally connected at the other end to the upper frame, means on the upper frame for moving the point of connection between the arm and said upper frame to change the angle of said arm toward and away from the vertical, whereby the height of the upper frame above the lower frame can be varied, a follower block slidable along a side rail of the upper frame, said other end of the lifting arm being pivotally connected to said block, the means for moving the point of connection being a screw operatively associated with the follower block and a crank for rotating said screw.
 2. A vehicle according to claim 1 which includes a friction brake arranged to restrict rotation of the screw. 